Those just learning about APIs will soon encounter three terms used in the field: API specification, API definition, and API documentation. Hearing them for the first time may be an intimidating experience. But once you break them down, you’ll gain a solid understanding of APIs work, what their parameters are, and what they’re capable of doing.
If you’re a stakeholder in the API field’s success, like a first-time developer or a product manager responsible for marketing it, this article is a must-read. It’ll help you comprehend all the work that goes into an API, from acquiring a toolset for it to documenting its life cycle. The information will also come in handy for API-related decision making, such as trying out a certain API specification or using hosted API documentation.
Without further ado, here’s everything you need to know about API specification, API definition, and API documentation.
API specification is a term that encompasses a broad understanding of the API’s behaviour. It’s a description format that references what the API’s functions are, how they are called, and what kind of responses users can expect. OpenAPI specification (formerly Swagger), which is currently available on software development host GitHub, is one concrete example that best illustrates this term. In the industry, OpenAPI is considered the go-to description format for RESTful APIs. It contains very thorough details on its API objects, functions, calls, and the interconnected relationships that all of these have.
The important thing to remember about API specification is that humans, not machines, are meant to engage with it. This is something meant for human staff to pore over, digest, and take guidance from. It is API definition that comprises the machine-related element, which you can learn more about below.
API definition is often confused with API specification. What the two have in common is that they both proffer explanations of how APIs work. But the two terms cannot be used interchangeably, as the manner in which they are engaged is very different.
While API specifications are meant to be deciphered by humans, API definitions are meant for machine consumption. This means that they should come in a format that is readable by machines. They’re used as standards for API tools so that the latter can generate API-related outputs. Some examples of these are code recipes that can be copied, pasted, and customized, software development kits (SDKs), and API documentation.
Lastly, API documentation pertains to guides on using the API. API docs are very much like the user manuals that come with tech gadgets or appliances. But the neat thing about API docs is that they don’t have to be as static as hard-copy user manuals. The industry now accommodates a number of hosted interactive toolsets for API documentation. Such a toolset might include a quick start guide, a list of API calls, response descriptions, error messages, tutorials, and sample code.
A hosted suite for API documentation helps a user visualize the API’s structure and expected responses. Moreover, it can give them the opportunity to tinker and customize sample code for themselves. And ultimately, this makes engaging with the API more fun and hands-on.
Applying Your Knowledge in API Development, Integration, and Acquisition
Now that you know the differences between these three terms, it should be easier for you to talk about APIs. The knowledge should be of value from both a technical and a business standpoint. It can be applied in all stages of the API’s life cycle, from its conception to its eventual adoption by a client.
Hopefully, this article has served as a good introduction to the expansive world of APIs.